1. Field of the Invention
This invention relates to closures for air bag assemblies and more particularly to such closures that include at least one movable door that closes an air bag deployment opening and is acted upon by an inflatable air bag to stress and separate a layer of foam and a flexible outer skin for forming a deployment path for the air bag.
2. Description of the Prior Art
Closures for air bag assemblies include those with a covering of smooth material such as polyvinyl chloride that is backed with a foam layer to form a soft cover for an air bag assembly that will hide door members that swing open when the air bag is deployed. Examples of such air bag assemblies are set forth in U.S. Pat. No. 4,852,907 which has unconnected door components that can be moved inwardly of the closure when an inwardly directed force is imposed by an occupant on the outer surface of the closure, for example if there is a head impact thereon or if hand or finger pressure is applied upon the outer surface. U.S. Pat. No. 5,046,758 discloses a hidden seam closure for an air bag assembly having a cutter for freeing a deployment door. U.S. Patent No. 4,952,351 shows a door that is molded in the top surface of an instrument panel but it has an observable seam line.
Other closures of this type such as shown in U.S. Pat. Nos. 5,082,310 and 3,640,546 provide a physical connection between the door members to prevent inward collapse through the retainer member. While suitable for their intended purpose such closures, such interconnection can increase the resistance to door opening movement which in turn can decrease the ability of the air bag to freely deploy once activated in response to vehicle impact.
Still other closures of this type such as shown in U.S. Pat. Nos. 5,131,678 and 5,215,330 an overlap feature to prevent inward deflection of the door member or members of the closure. While such closures avoid the drawback of an interconnection, the particular arrangements disclosed in these patents are not entirely satisfactory. For instance the single door arrangement shown in U.S. Pat. No. 5,131,678 has an observable seam line. On the other hand the double door arrangement shown in U.S. Pat. No. 5,215,330 does not provide any support for the underlying door member.